The Tissue Processing and Cell Culture Core Unit will provide centralized facilities for use by Projects I, II, and III. Services provided will include routine histology, preparation of cells and tissues for immunofluorescence microscopy, culture of lymphocytes, and maintenance of cell lines. Equipment for these procedures is available, and an experienced technician will carry them out. This will ensure prompt and economic use of tissue and cell preparations for distribution among the project users, promote uniform standards involving unique immunofluorescence reagents, and provide a central source of relevant advice and information.